When I lived in the DFW
area I would often travel between DFW
both by car and plane and personally I enjoyed driving more than flying especially if I was not traveling by myself. Depending on the type of car you have you will probably spend between $180 and $200 in gas plus wear and tear but you will have your own vehicle to use in MSY
rather than paying for a rental. As mentioned above you will get more and better food for your money on the road. Another advantage to driving to MSY
is that you can be half way down the road in the time it would take to get to the airport, deal with checking in and going thru security, flying, recovering any checked luggage and picking up a rental car. The drive really is not too bad especially if you leave early in the morning from DFW
Anyway, have a great trip no matter which mode you choose!